A new genus, Idatenopsocus, represented by Idatenopsocus orientalis (Vishniakova, 1986), comb. nov., is described and the species is redescribed. Within the family Mesopsocidae, this new genus is considered as the sister group of a monophyletic group composed of the genera Mesopsocus, Microtrichipsocus, Metapsocus, Cyrtopsochus, Hexacyrtoma, and Rhinopsocus.